This invention relates to a method for performing an anterior capsulotomy during a cataract extraction and particularly to a method using an instrument designed to make the task simpler and more adequate.
In the past decade cataract extraction by the extracapsular technique has returned as a common method of cataract extraction, replacing in part intracapsular cataract extraction method. During extracapsular cataract extraction the anterior capsule of the lens is incised to allow its removal and to allow access to the underlying cortex and nucleus of the lens for their eventual removal. The most common method used today for an anterior capsulotomy is to use a small sharp hook called a cystotome. Through a small incision in the peripheral cornea, small connecting tears are made in the anterior lens capsule in a circular pattern around the periphery of the lens capsule. When a complete circle has been made by connecting the tears, the anterior capsule of the lens is free to be removed.
The cystotome method is combersome, time consuming and leaves tags of anterior capsule which often interfere with later removal of the cortex of the lens. In addition, traction on one of these tags can lead to a tear extending posteriorly into the posterior capsule of the lens; this is a significant complication. Furthermore, during the anterior capsulotomy by this method the cystotome often inadvertently and unknowingly slips below the level of the capsule. The operator is then given the false impression that he is cutting anterior capsule when in fact he is making an incision in the subjacent lens cortex. As a result, an inadequate opening is made in the anterior capsule. Finally, when the pupil is small, the procedure by the cystotome method becomes very difficult.
If the central cornea is removed as during a cornea transplant a very large opening is made into the eye. Through this large opening a scissors or conventional knife can be used to make a smooth circular incision into the anterior capsule. This could circumvent many of the above mentioned problems. Such a large incision, however, is impractical for routine cataract extractions.
The method and instrument herein described are designed for a simple anterior capsulotomy which is both performed through a small incision and leaves behind a smooth circular anterior capsule edge.